The issue with the rear engined vs. mid engined is the very point/aberration I was referring to
The B51 wasn't bought in great numbers. LCBS had a large batch but there were many others only bought a handful. It was perhaps that it arrived at the wrong time - the change to coach licensing meant that standards were much higher and the Paramount 3200 or Duple Laser were much more comfortable (reflecting their use on local expresses and Nat Ex work). It also arrived after the end of the bus grant and that had an impact on the DP coach
It was better than the Willowbrook 003, of that I can't disagree. My father's depot had one delivered new and it was clearly rubbish from the start, one of
25 in the fleet.
You're right that Drawlane had a lot of LCBS Tigers that didn't really have a role and had an NBV that they wouldn't recoup from selling (with ECW and Berkhof bodies that didn't have the best of reputations - rightly or wrongly) and so rebodying with EL2000s and allowing the replacement of many knackered, unreliable and thirsty MRN Nationals made a lot of sense.
BTW, the TDs were leased from Kirkby Kingsforth and returned off lease, whereas the TLs were owned so that explains their retention.